1. Field of the Invention
The present invention relates to a pipeline beads mill for use as an independent dispersing apparatus for dispersing a material to be treated, such as a slurry or mill base in which solid particles are suspended in a liquid, or for use in a feeding line for preliminary dispersion treatment of the material to be treated prior to dispersion of the material by a dispersing apparatus. The present invention also relates to a dispersing system having the pipeline beads mill.
2. Background Information
In the chemical field, various products, such as coating materials, printing inks, pigments and magnetic materials, are produced using a stirring treatment. In the case of materials to be treated having high viscosity, as well as materials (e.g., a slurry) having low or medium viscosity, a relatively large power is required for conducting a uniform stirring treatment. Particularly, in the case in which a dispersing apparatus, such as, for example, a wet-type medium-dispersing apparatus, is used to finely grind a material to be treated by stirring it together with a dispersion medium, such as beads, a pre-treatment (pre-mixing) operation which involves preliminarily stirring the material to be treated is conducted before feeding the material to be treated to the dispersing apparatus. It is commonly known that if the material to be treated is simply stirred in such pre-treatment operation, primary particles can hardly be formed from solids (e.g., powder) and a large amount of secondary agglomerates is deposited in the pipelines. Such deposit of secondary agglomerates has a large negative influence in the cleaning property of the pipelines and has caused contamination problems.
Further, by the presence of a large amount of secondary agglomerates as mentioned above, when the dispersion treatment is carried out using a wet-type medium-dispersing apparatus or the like, it takes a long period of time for dispersion to finely grind the material to a desired particle size. In addition, the secondary agglomerates tend to cause clogging of a screen or the like disposed in the medium-dispersing apparatus for the purpose of separating the dispersion media, such as beads, from the material to be treated, thereby deteriorating the operation efficiency of the dispersing apparatus.
It is an object of the present invention to provide a pipeline beads mill by which when a material to be treated, such as a slurry, is subjected to dispersion treatment with a dispersing apparatus, such as a wet-type medium-dispersing apparatus, secondary agglomerates are disintegrated for preliminary dispersion during the passage of the material to be treated in a feeding line.
It is another object of the present invention to provide a pipeline beads mill which efficiently disintegrates secondary agglomerates in a material to be treated prior to feeding the material to be treated into a dispersing apparatus, thereby reducing the time and power required by the dispersing apparatus to disperse the material to be treated.
It is another object of the present invention to provide a pipeline beads mill which can be used as an independent dispersing apparatus for dispersing a material to be treated.
It is another object of the present invention to provide a pipeline beads mill which is compact and which can be easily connected to and disconnected from a feeding line of a material to be treated for repair and cleaning operations.
It is yet another object of the present invention to provide a dispersing system utilizing a pipeline beads mill for subjecting a material to be treated to a preliminary dispersion treatment prior to dispersion of the material to be treated by a dispersing apparatus.
The foregoing and other objects of the present invention are carried out by a pipeline beads mill comprising a dispersion chamber, a first feeding port for feeding a material to be treated into the dispersion chamber, a second feeding port for feeding a dispersion media into the dispersion chamber, a tubular outer stator disposed in the dispersion chamber, and a tubular inner stator disposed in the outer stator in spaced-apart relation thereto to form a treatment gap therebetween for receiving the dispersion media and the material to be treated. The inner stator has an outflow port in communication with the treatment gap. A tubular rotor is disposed in the dispersion chamber and partitions the treatment gap into an outer gap portion and an inner gap portion. A rotational drive shaft rotates the rotor to displace the dispersion media so as to disperse the material to be treated. The rotor has a circulation port for permitting circulation of dispersion media between the outer gap portion and the inner gap portion of the treatment gap during rotation of the drive rotor. A discharge port is disposed in communication with the outflow port of the inner stator for discharging the dispersed material. A separating member is disposed at an inner side of the outflow port of the inner stator for separating the dispersion media from the dispersed material and permitting the dispersed material but not the dispersion media to be discharged from the discharge port of the dispersion chamber.
Preferably, axial flow blades are disposed on the rotational drive shaft for generating an axial flow to direct the material to be treated from the first feeding port to the discharge port. A flow-control surface (e.g., a non-flat surface, a projection, or a spiral groove) is preferably formed on at least one of the outer and inner surfaces of the rotor, an inner surface of the outer stator and an outer surface of the inner stator which are disposed in confronting relation to the treatment gap. In an alternative embodiment, the outer and inner surfaces of the rotor, the inner surface of the outer stator and the outer surface of the inner stator are disposed in confronting relation to the treatment gap and comprise generally flat and smooth surfaces.
Preferably, the rotor has a generally conical-shaped upper surface portion. A tubular main body of the pipeline beads mill has an inwardly projecting portion disposed over the upper surface portion of the rotor and forms an inflow port in communication with the dispersion chamber. A generally conical-shaped gap is disposed between the inwardly projecting portion and the upper surface portion of the rotor and in communication with the outer gap portion of the treatment gap. An outflow-preventing projection is preferably formed on at least one of the upper surface portion of the rotor and an inner surface of the inwardly projecting portion disposed in confronting relation to the conical-shaped gap for preventing the outflow of dispersion media through the inflow port.
In another aspect, the present invention is directed to a dispersing system having a stirring tank for stirring a material to be treated. The stirring tank has an inlet port and an outlet port. A dispersing apparatus is connected to the stirring tank for dispersing the material to be treated in a dispersion chamber by displacing dispersion media disposed in the dispersion chamber and in contact with the material to be treated. The dispersing apparatus has an inlet port for feeding the material to be treated into the dispersion chamber and an outlet port for discharging the material to be treated after dispersal thereof. A pipeline beads mill is disposed between the stirring tank and the dispersing apparatus for preliminarily dispersing the material to be treated after the material is stirred in the stirring tank but prior to dispersion of the material by the dispersing apparatus. The pipeline beads mill has a dispersion chamber, a first feeding port for feeding a material to be treated into the dispersion chamber, a second feeding port for feeding a dispersion media into the dispersion chamber, a tubular outer stator disposed in the dispersion chamber, and a tubular inner stator disposed in the outer stator in spaced-apart relation thereto to form a treatment gap therebetween for receiving the dispersion media and the material to be treated. The inner stator has an outflow port in communication with the treatment gap. A tubular rotor is disposed in the dispersion chamber so that the treatment gap is partitioned into an outer gap portion and an inner gap portion. A rotational drive shaft rotates the rotor to displace the dispersion media so as to disperse the material to be treated. A discharge port is disposed in communication with the outflow port of the inner stator for discharging the dispersed material. A separating member is disposed at an inner side of the outflow port of the inner stator for separating the dispersion media from the dispersed material and permitting the dispersed material but not the dispersion media to be discharged from the discharge port of the dispersion chamber.
Preferably, a particle size of the dispersion media contained in the treatment gap of the pipeline beads mill is from 2 to 4 times greater than a particle size of the dispersion media contained in the dispersion chamber of the dispersion apparatus.